β-NMR Studies of the Depth Dependence of Secondary Relaxations in Polystyrene Thin Films

ORAL

Abstract

β-detected nuclear magnetic resonance (β-NMR) of implanted 8Li+ has been used to probe the depth dependence of secondary relaxation processes in thin films of atactic polystyrene (PS). β-NMR measurements of the average 8Li spin-lattice relaxation rate were used to determine the depth dependence of the fluctuation rate of the fast γ-relaxation process in PS films at 317 K, which is well below its glass transition temperature [I. McKenzie et al. Soft Matter, 14, 7324 (2018)]. A novel hole-burning (selective saturation) β-NMR technique has been used to measure the depth dependence of the fluctuation rate of the much slower β-relaxation process at the same temperature. Both the fluctuation rates of the β- and γ-relaxation processes are larger near the free surface than in the bulk and both return to the bulk value over a length scale of several nm.

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Presenters

  • Iain McKenzie

    • Physical Sciences Division, TRIUMF

Authors

  • Iain McKenzie

    • Physical Sciences Division, TRIUMF

  • Yu Chai

    • Lawrence Berkeley National Lab
    • Physics and Astronomy, University of Waterloo

  • David Cortie

    • Physics and Astronomy, University of British Columbia
    • University of Wollongong

  • James Forrest

    • Physics and Astronomy, University of Waterloo
    • University of Waterloo

  • Derek Fujimoto

    • Department of Physics and Astronomy, University of British Columbia
    • Physics and Astronomy, University of British Columbia

  • Victoria Karner

    • Departament of Chemistry, University of British Columbia
    • Chemistry, University of British Columbia

  • Robert F Kiefl

    • Department of Physics and Astronomy, University of British Columbia
    • Physics and Astronomy, University of British Columbia
    • Department of Physics & Astronomy and Stewart Blusson Quantum Matter Institute, University of British Columbia

  • CDP Levy

    • Accelerator Division, TRIUMF

  • W Andrew MacFarlane

    • Departament of Chemistry, University of British Columbia
    • Chemistry, University of British Columbia
    • Department of Chemistry, University of British Columbia

  • Ryan McFadden

    • Departament of Chemistry, University of British Columbia
    • Chemistry, University of British Columbia

  • Gerald D Morris

    • Center for Molecular and Materials Science, TRIUMF, Vancouver, BC V6T 2A3, Canada
    • Physical Sciences Division, TRIUMF
    • TRIUMF
    • TRIUMF, Vancouver, British Columbia V6T 2A3, Canada.

  • Matthew Pearson

    • Physical Sciences Division, TRIUMF

  • Adam Raegen

    • Physics and Astronomy, University of Waterloo
    • University of Waterloo

  • Shipei Zhu

    • Physics and Astronomy, University of Waterloo